I couldn't think of any other reason why.
How about the pool ping? You might have a slow internet connection that leads to share submission delays.

Or maybe your current network is infected bitmain has a solution to this you can check the link below or use APtool to scan your network and miners.

- https://support.bitmain.com/hc/en-us/articles/360009975634-Viruses-Malware-and-Remote-Attacks-on-ANTMINER-How-to-prevent-and-remove-them-

I hope that you can share your miner's status screenshot here to give us some clues.